Sacred populations of Cercopithecus sclateri: analysis of apparent population increases from census counts.

The development of effective conservation and management actions for populations of wild species generally requires monitoring programs that provide reliable estimates of population size over time. Primate researchers have to date given more attention to evaluating techniques for monitoring primates in natural habitats compared to populations that occur in villages or urban areas. We conducted censuses to estimate the abundance and density of two sacred, village-dwelling populations (Lagwa and Akpugoeze) of Sclater's monkey (Cercopithecus sclateri), a threatened species endemic to southeastern Nigeria, and compared these data to previous census results. We recorded population increases in both sites: a 66% increase over 4½ years in Lagwa (from 124 to 206 individuals) at an annual rate of 10.2%, and a 29% increase over 4 years in Akpugoeze (from 193 to 249 individuals) at an annual rate of 5.7%. Mean group size also increased in both sites. Density in Lagwa was 24.2 individuals/km(2) , and density in a core survey area of Akpugoeze was 36-38 individuals/km(2) . Our results may have been affected by monkey ranging and grouping patterns and improved detectability due to our revised census technique, which included secondary observers. With further work on methodology for censusing populations that occur in human-settled environments, techniques can be refined and customized to individual sites for more accurate estimates. Our investigation of Sclater's monkey in Lagwa and Akpugoeze, two sites critical for conservation of the species, indicated that both of these populations have increased, and neither faces immediate risk of extirpation. Such population growth, while encouraging, will likely exacerbate human-monkey conflict and thus should be understood in terms of potential socioeconomic impacts.

Distribution and abundance of sacred monkeys in Igboland, southern Nigeria.

Although primates are hunted on a global scale, some species are protected against harassment and killing by taboos or religious doctrines. Sites where the killing of sacred monkeys or the destruction of sacred groves is forbidden may be integral to the conservation of certain species. In 2004, as part of a distribution survey of Sclater's guenon (Cercopithecus sclateri) in southern Nigeria, we investigated reports of sacred monkeys in the Igbo-speaking region of Nigeria. We confirmed nine new sites where primates are protected as sacred: four with tantalus monkeys (Chlorocebus tantalus) and five with mona monkeys (Cercopithecus mona). During 2004-2006, we visited two communities (Akpugoeze and Lagwa) previously known to harbor sacred populations of Ce. sclateri to estimate population abundance and trends. We directly counted all groups and compared our estimates with previous counts when available. We also estimated the size of sacred groves and compared these with grove sizes reported in the literature. The mean size of the sacred groves in Akpugoeze (2.06 ha, n = 10) was similar to others in Africa south of the Sahel, but larger than the average grove in Lagwa (0.49 ha, n = 15). We estimated a total population of 124 Sclater's monkeys in 15 groups in Lagwa and 193 monkeys in 20 groups in Akpugoeze. The Akpugoeze population was relatively stable over two decades, although the proportion of infants declined, and the number of groups increased. As Sclater's monkey does not occur in any official protected areas, sacred populations are important to the species' long-term conservation. Despite the monkeys' destruction of human crops, most local people still adhere to the custom of not killing monkeys. These sites represent ideal locations in which to study the ecology of Sclater's monkey and human-wildlife interactions.